<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>testtypeof</title>
</head>
<body>
<script>
function foo() {
  let a = b = 0;
  console.log('a---:',a)
  console.log('b---:',b)
  a++;
  return a;
}

foo();

// console.log('a:',a)
console.log('b:',b)
console.log('typeof a:',typeof a)
console.log('typeof b:',typeof b)

</script>
</body>
</html>
